This invention relates to a turbulence generator for two-stroke spark assisted diesel engines and more particularly to an improved arrangement for ensuring good, complete combustion in an engine of this type.
Because of the high fuel efficiency of a diesel engine, there is considerable interest in widen applications for engines of this type. However, the extremely high compression ratios employed with conventional diesel engines and the attendant weight necessary to compensate for the high stresses created by these high compression ratios has limited the application of diesel engines. For example, there are particular advantages in being able to employ a diesel engine in connection with an outboard motor. However, outboard motors must, of their very nature, be quite light in weight and thus conventional diesel engines have not enjoyed wide popularity in this form of application.
Most outboard motors are operated on the two-cycle principle because of the high output possible with such engines due to the higher frequency of firing than with four-cycle engines. However, the two-cycle engine has a defect in that it normally has a higher specific fuel consumption than a four-cycle engine. Therefore, there are certain advantages to the application of diesel engines for two-cycle outboard motors. Again, however, the high weight associated with conventional diesel engines has limited their use in outboard motors.
It has been proposed to reduce the weight of a diesel engine by employing a lower than normal compression ratio. While most diesel engines operate with compression ratios in the range of 17:1, it is possible to provide diesel operation with compression ratios of 12:1 and under. To insure complete combustion, it is necessary with such lower compression engines to employ a spark plug for assisting ignition in at least some of the running conditions. However, there still remains the problem of insuring complete combustion during the running cycle of such an engine to insure the advantages of good fuel economy as well as high power output.
It is, therefore, a principal object of this invention to provide an improved combustion chamber configuration and method of operating an engine to insure good combustion efficiency and high power output.
It is further object of this invention to provide an improved combustion chamber configuration and method of operating an engine to insure complete combustion on a diesel cycle.
It is a yet further object of this invention to provide an improved combustion chamber for a spark assisted diesel engine.